Method of separating a sulfonic acid of a hydrocarbon of the aromatic series from sulfuric acid and of converting the sulfonic acid into a salt.



- sulfonic acid of a hydrocarbon of the arc-' sra i LOUIS M. DENNIS, 0FITHACA, NEW YORK.

METHOD OF SEPARATING A SULFONIC ACID 0]? A HYDBOCARBON OF THE AROMATICSERIES FROM SULFURIC ACID AND OF CONVERTINGTHE SULFONIC ACID INTO ASALT.

messes.

Specification of Letters Patent.

Patented 31111612, 191?.

No Drawing. Original application filed December 18, 1915, Serial No.67,535. Divided and this application filed November 6, 1916. Serial No.129,658..

To all whom it may concern:

Be it known that I, LOUIS M. Dennis, a

siding at Ithaca, Tompkins county, New York, have invented certain newand useful improvements in methods of separating a matic series fromsulfuric acid and ofconverting the sulfonic acid into a salt, of whichthe following is a specification.

, My invention relates to methods of sepa: rating a sulfonic acid of ahydrocarbon of the aromatic series from sulfuric acid and resultingeconomies in cost roduction.

In my application Serial 0. 67 ,535, filed December 18, 1915, of whichthis is a division, I have described and claimed one of the ways bywhich my process may be carried out. In this I shall claim another way.

I shall illustrate my invention by describing the making of sodiumbenzene sulfonate although the invention is not restricted to the makingof such salt alone.

It has been the general commercial practice in making salts of benzenesulfonic acid, specifically sodium benzene sulfonate, to treat benzenewith fuming sulfuric acid to produce benzene sulfonic acid in thepresence of an excess of sulfuric acid; this mixture is then usuallytreated with lime and a sodium compound, which forms chiefly calciumsulfate and sodium benzene sulfonate; these two salts are then separatedby treatment with water which dissolves the sodium benzene sulfonatewith a little ofthe served that the excess of sulfuric acid which of ahydrocarbon. of the aromatic series. from has not reacted with thebenzene is converted mto the comparatively valueless calcium sulfate andthus lost.

By my method, I avoid the use of lime and consequent production ofcalcium sulfate; I avoid the consequent necessary sep-' aration byfiltration; I avoid the evaporation of dilute solution and recover theexcess of sulfuric acid which has not-reacted with'the benzene.

In carrying out my process I treat the mixture of benzene sulfonic acidand sulfuric acid, formed as above stated, with benzene which dissolvesthe .benzene sulfonic acid but not the sulfuric acid. The solution ofbenzene sulfonic acid in benzene, which separates from the residualsulfuric 70 acid-in a distinct layer is thentreated with 7 water whichdissolves out the sulfonic acid from the benzene. The resulting watersolution is then neutralized by being brought into contact with asuitable base or compound, such as an aqueous solution of sodiumhydroxid, and the salt is separated out by evaporation of the water. The,benzene thus set free may be used again in the extraction of furtherportions of benzene sulfonicacid from a fresh mixture of the same. withsulfuric acid. The sulfuric acid which remains after the benzenesulfonic acid has been removed from it by the benzene is drawn ofiandfused for I any desired purpose. 1 p v It is obvious that othersolvents than hen-F zene may be used to dissolve" the sulfomc" 3 acidand that other salts thanthe sodiumsalt of said acid may beproduced bythe use of suitable bases or other compounds.

I claim: i

1. A, method of. separating a sulfonic acid of a hyrocarbon of thearomatic series from sulfuric acid consisting in treating ajmixture ofthe acids with a solvent which is relatively insoluble in water, and inwhich sulfuric acid is relatively insoluble, separating the solution ofsulfonic acid in the solvent from sulfuric. acid andv substanttallyfreeing the solvent from the-sulfonie acid by; treating the same with wateto dissolvejand (1.51s retain the sulfonic acid. j.

2. A method of separating a'sulfonic acid I sulfuric acid consisting in"treating a mix! ture ofthe" acids with an organic. solvent 5 in theorganic solvent from sulfuric acid and substantially freeing the solventfrom i the sulfonic acid by treating the same with water to dissolve andretain the sulfonic id 7 1 v 3. A method of separating a sulfonic acidof a hydrocarbon of the aromaticseries from sulfuric acid consisting intreating a mixture of the acids with benzene, separat1ng I the sulfuric.acid and substantially'freeing the benzene from the sulfonic acid bytreating the same with water to dissolve and retain the sulfonic acid. I

4. A method of separating benzene sulfonic acid from sulfuric acidconsisting in treat ing a mixture of the acids with benzene, se aratingthe. benzene solution of benzene su fonic .acid from the sulfuric acidand substantially freeing the benzene from the benzene sulfonic acid bytreating the sam with water to dissolve and retain, the sulfonic acid. l5. A method of making a salt ofa sulfonic acid of a hydrocarbon of thearomatic 80 series consisting in treating a mixture of the sulfonic acidand sulfuric acid with a solvent which is relatively insoluble in waterand. in which the sulfuric acidis relatively insoluble, separating thesolution of sulfonic acid in the solvent from sulfuric acid, treatingthe solution withwater to dissolve and retain the sulfonic acid andtreating said aqueous solution with a suitable compound I capable ofreacting on the sulfonic acid in aqueous solution to form a salt,

6. A method of making a salt of a sulfonic acid of ahydrocarbon' of thearomatic series consisting in treating a mixture of the sulfonic acidand sulfuric acid with an organic solvent which is relatively insolublein water and in which the sulfuric acid is relatively insoluble,separating the solution of sulfonic acid in the organic solvent fromsulfuric acid, treating the solution with water to'dissolve and retainthe'sulfonic acid and treating said aqueous solution with a suitable.compound capable of reacting on the sulfonic acid in aqueous solution toform a salt.

acid from sulfuric acid, treating the solution with water to dissolveand retain the sulfonic ac d and treating the said aqueous .solutionwitha smtable compound capable of reacting on the sulfonic acid in aqueoussolution to form a salt.

the benzene solution of sulfonic acid from.

7. A method of making a salt of a sul- I masses SJA method of making thesodium salt of a sulfonic acid of a hydrocarbon of the aromatic seriesconsisting in treating a mixture of the sulfonic acid and sulfuric acidwith benzene, separating the'benzene solution of sulfonic acid fromsulfuric acid, treating the solution with water to'dissolve and retainthe sulfonic acid and treating said aqueous solution with a suitablesodium compound capable of reacting on the sulfonic acid in aqueoussolution to form its sodium salt.

9. A method of making the sodiumsalt of a sulfonic acid of a hydrocarbonof the aromatic series consisting in treating a mixture of the sulfonicacid and sulfuric acid with benzene,rsepara ting the benzene solution ofsulfonic acid from sulfuric acid, treating the solution with water todissolve and retain the sulfonic acid and treating said aqueous solutionwith sodium hydroxid.

10. .A method of making a salt of henzene sulfonic' acid consisting intreating a mixture of the sulfonic ,acid and sulfuric acid with asolvent which is relatively insoluble in waterand in which sulfuric acidis relatively insoluble, separating the solution of benzene sulfonicacid in the solvent from sulfuric acid, treating the solution with waterto dissolve and retain the sulfonic acid and treating said aqueoussolution with a suitable compound capable of reacting on the sulfonicacid in aqueous solution to form a salt. a

11. A method of making a salt of henzene sulfonic acid consisting intreating a mixture of the sulfonic acid and sulfuric acid with anorganic solvent which is relatively insoluble in water and in whichsulfuric acid is relatively'insoluble, separating the solution ofbenzene sulfonic acid in the organic solvent from sulfuric acid,treating the solutiouwith water to dissolve and re tain the sulfonicacid and treating said aqueous solution with a suitable compound capableof reactingon the sulfonic acid in aqueous solution to form a salt.

12. A method of making a salt of ben= zene sulfonic acid consisting intreating a mixture of the sulfonic acid and sulfuric acid with benzene,se arating the benzene solution of benzene sulfonic acid from sulfuricacid, treating the solution with water to dissolve and retain thesulfonic acid and treating said aqueoussolution with a suit ablecompound capable of reacting on the sugfonic acid in aqueous solution toform a sa t,

13. A method of making sodium benzene I and retain the sulfonic acid andtreating said aqueous solution with a suitable sodium compound capableof reacting on the sulfonic acid in aqueous solution to form its sodiumsalt.

14. A method of making a sodium benzene sulfonate consisting in treatinga mixture of benzene sulfonic acid and sulfuric acid with benzene,separating the benzene 7 solution of benzene sulfonic acid from sul- 10In testimony whereof I have signed this 15 specification.

ouis M; DENNIS. V

